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## Characteristics of waves

Amplitude- maximum displacement of a point on a wave, away from it's undisturbed position.

Frequency- the number of waves passing a point each second and it measured in hertz (Hz)

Wavelength- is the distance from a point on one wave to the same point on the adjacent wave and is measured in metre (m)

Period- time taken for a particle to undergo one vibrational cycle measured in seconds (s)

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## What are electromagnetic waves?

Electromagnetic waves are waves that are created as a result of vibrations between a magnetic and electric field

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## What are the seven types?

Microwaves (15cm)                               Marshmallows

Visible light                                          Venus

Ultraviolet (500 nanometers)                  Using

X-rays (0.1 nanometres)                        X-ray

Gamma rays (0.000001 nanometres)      Guns

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## Typical uses

Microwaves- cooking, mobile phones

Infrared- optical fibre, communication

Visible light- seeing

Ultraviolet- detecting forged bank notes

X-rays- medical images of bones

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## Typical dangers

Radio waves- safe unless very concentrated

Microwaves- burning if concentrated

Infrared- burning if concentrated

Visible light- burning, blindness if concentrated

Ultra-violet light- sunburn, skin cancer

X-rays- cell destruction, cell mutation, cancer

Gamma rays- cell destruction, cell mutation, cancer

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## Why do all waves travel at the same speed?

In general, loght travels in waves and all electromagnetic radiation travels at the same speed which is about 3.0 × 10^8 per second through a vacuum. This is called the 'speed of light', nothing can move faster than this.

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## Properties of electromagnetic waves and how are th

• Carry transverse vibrations in electrical and magnetic fields, not vibrating particles.
• Don not need matter to travel through, can travel through a vacuum
• In a vacuum, all waves travel at approximately  3 ×10^8- the fastest speed possible
• When the waves travel though matter that travel a bit slower than this but less than 1/2 as fast in a vacuum.

An electromagnetic wave can be creates by accelerating charges, moving charges back and forth will produce oscillating electric and magnetic fields.

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## Wave equation

Wave speed (v) = frequency (f) × wavelength( λ)

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